We... already have a treatment for HIV after you get it. The cocktails are now such that HIV has very little effect on life expectancy.

I would PM you if I could. don't even know if slashdot has that functionality. email me, krisrhodes at gmail.

The practical boundary is certainly microfossil measured, but those aren't as good a world-wide unique time stamp as the iridium anomaly - which in theory is uniform through the world and specific in time to a one year or so period. So yeah, no real disagreement here, but I'm also not about to start reading papers looking for the consensus K-T boundary either.

They only have one picture of the "fossil" in the paper, and to be honest - it doesn't look like one to me. Preservation looks absolutely terrible. They don't really talk about preservation. It doesn't look like there is more of the animal there (which does, of course, highly support transport). If you can't access the paper, let me know and I'll send it.

It is my understanding that the "official" K-Pg was defined based on the iridium spike, even though that was not what was used in this study.

But there isn't a -gap-. There is uncertainty as to the exact timing. A gap is a period when you are sure there isn't anything; uncertainty means you don't know. To the best of our knowledge - and constantly improving as more work is done - the uncertainty periods are getting smaller. This is evidence for concurrence. Concurrence is not disproven, and the evidence that supports it keeps getting better as it is refined.

There are no terrestrial beds of fossil bearing rock that also contain unequivocal markers of the K-T iridium spike. That's why we have correlation. There are lots of continuous beds of fossil bearing rock that do contain the K-T and show evidence of mass extinction - in the marine realm. Foram extinction and population is well documented and not disputed, as well as other marine creatures. The most likely explanation is that the impact had some role in the extinction.


|...as the one true theory....

The article doesn't claim anything about one true theory, and neither did I. Straw man at it's best. Scientists look for evidence and weigh it. I recommend you learn more about Bayes theorem and then reexamine the evidence.

Gradual extinction is still a possibility, but that's been covered by other studies and there is little to no evidence that specifically supports it.

What this paper does way in on is the claims that the extinction happened a long time (3m of rock worth of time) before the impact. If this is an unreworked bone, those claims are dead.

>Sedimentation rates are estimated to have ranged from 52 to 81 meters per million years. Thus 13 cm represents no more than 2500 years.

Sedimentation rates are not constant. They tend to come in fits and bursts. I would not draw that conclusion from the evidence.

The thing is - if they were in fact concurrent - then we'd expect that as better data becomes available, the dates converge.

This is exactly what has happened over time. There's actually new work being done by Zircon workers that continues to close the gap.

And yes, this IS evidence that supports that dinosaurs went extinct at the boundary. It increases the possibility of that, to the exclusion of others possibilities, by at least a little bit.

Hell Creek formation = fluvial (river) deposits.

Reworking is always a possibility.

This specific fossil is claimed to have been found in an overbank deposit, which means that it was out on the flood plain, which if true means it is unlikely to have been reworked. But I'd want to see it for myself.